Blends comprising epoxy resins and mixtures of amines with guanidine derivatives

ABSTRACT

The present invention provides a blend comprising one or more epoxy resins and a mixture which comprises 0.3 to 0.9 amine equivalent, per equivalent of epoxide of the epoxy resin used, of a hardener component a) and as hardener component b) a compound of the formula I, a process for preparing this blend, the use of the blend of the invention for producing cured epoxy resin, and an epoxy resin cured with the blend of the invention.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. Ser. No. 13/055,174(now U.S. Pat. No. 8,741,426), filed Apr. 15, 2011, which was a 371 ofinternational PCT application PCT/EP2009/059238, filed Jul. 17, 2009.The present application further claims priority to European applicationEP 08150857.2, filed Jul. 22, 2008 in the European Patent Office, andPCT/EP2009/058699, filed Jul. 8, 2009.

The present invention provides a blend comprising one or more epoxyresins and a mixture which comprises 0.3 to 0.9 amine equivalent, perequivalent of epoxide of the epoxy resin used, of a hardener componenta) and as hardener component b) a compound of the formula I, a processfor preparing this blend, the use of the blend of the invention forproducing cured epoxy resin, and an epoxy resin cured with the blend ofthe invention.

The amine curing of epoxy resins is utilized in a very wide variety ofsegments. For instance, the amine curing of epoxy resins is employed inthe context of adhesives, for the curing of casting resins in specialmolds, and also for the sealing of surfaces and components to beprotected from environmental effects.

One specific, large field of application of the amine curing of epoxyresins is the production of fiber-reinforced plastics. Fiber-reinforcedplastics are used as materials of construction for motor vehicles,aircraft, ships and boats, for sports articles and for rotor blades ofwind turbines.

The production of large components imposes particular requirements onthe hardener or hardener mixture, since during the processing life theviscosity must not rise so sharply that either the fibers are notadequately wetted or else the mold is not completely filled before theepoxy resin becomes no longer processable.

At the same time there ought not to be any adverse effect on the cycletime (processing and curing). Consequently there is a great need formixtures which are capable of precisely controlling and setting thecuring of the epoxy resin in any systems.

H. Klein, in “Huntsman Amine Overview”, Huntsman, Jun. 19, 2007, BeijingEpoxy Conference, describes how primary and secondary diamines andpolyetheramines can generally be used to cure epoxy resins. A blend inwhich the hardener component a) is used in the range from 0.3 to 0.9amine equivalent, per equivalent of epoxide of the epoxy resin used, andin which the hardener component b) is a compound of the formula I, isnot described, however.

B. Burton, D. Alexander, H. Klein, A. Garibay Vasquez, and C. Henkee, inthe product brochure “Epoxy formulations using JeffaminePolyetheramines”, Huntsman, Apr. 21, 2005, describe the stoichiometricuse of polyetheramines, or a mixture of polyetheramines and otherdiamines such as isophoronediamine (IPDA), as a particular form of theamine curing of epoxy resins. The systems in question are two-componentsystems in which the amine or amine mixture is added to the epoxy resinimmediately prior to curing, in amounts which comprise exactly the samenumber of active amine functions in the amine mixture as there areactive epoxide functions in the epoxides.

In hardener formulations comprising polyetheramines and IPDA, the effectof the latter is on the one hand a higher cure rate and on the otherhand the observation of higher glass transition temperatures in thecured resins, leading to a higher temperature stability on the part ofthe cured products—as required for certain applications such as theproduction of rotor blades, for example—than is the case with curing atcomparable temperature using pure polyetheramine.

As compared with the curing of epoxy resins by polyetheramines, however,the addition of IPDA entails not only a higher glass transitiontemperature on the part of the cured resins but also more rapid curing,which is accompanied by a more rapid increase in viscosity. As a result,the time within which the blend of epoxy resin and hardener/hardenermixture can still be processed is reduced. A disadvantage with hardenermixture systems of this kind, therefore, is that the production of largecomponents, such as rotor blades, is possibly unsuccessful, because theinfusion process remains incomplete on account of the development ofviscosity.

The rate of the stoichiometric curing of epoxy resins with amines canalso be increased by adding tertiary amines to the blend, which functionas accelerants. This addition as well leads usually to a more rapidincrease in viscosity at room temperature and to shorter pot lives. Thepot life or else gelling time is a variable which is commonly utilizedto compare the reactivity of different resin/hardener combinationsand/or resin/hardener mixture combinations. The measurement of potlife/gelling time (To) is described according to the specification ofASTM D 2471-99 and is a method of characterizing the reactivity oflaminating systems by means of a temperature measurement. Depending onapplication, deviations from the parameters described therein (amount,test conditions, and measurement method) have become established,resulting in a pot life A (ToA) and a pot life B (ToB).

The pot life A (ToA) is determined as follows:

100 g of the blend, comprising epoxy resin and hardener or hardeningmixture, are introduced into a container (typically a cardboard carton).A temperature sensor is immersed into this blend, and measures andstores the temperature at defined time intervals. As soon as this blendhas solidified, measurement is ended and the time taken to attain themaximum temperature is determined. Where the reactivity of a blend istoo low, this measurement is carried out at elevated temperature. Aswell as the pot life, it is always necessary to report the testingtemperature as well.

Pot life B (ToB) is determined as follows:

5 g of the blend comprising epoxy resin and hardener/hardener mixtureare introduced in a 5 ml penicillin bottle at a given testingtemperature (not adiabatically). A circular die (Ø 11.8 mm) moves up anddown (1 mm/sec) in the blend. When a corresponding resistance (about 5kPa) is reached, the stopwatch is shut off.

Examples of above-described accelerants specified in U.S. Pat. No.4,948,700, column 10, are triethanolamine, benzyldimethylamine,2,4,6-tris(dimethylaminomethyl)phenol, and tetramethylguanidine. Thefundamental suitability of tetra- and penta-alkylguanidines as hardenersof epoxy resin mixtures is described in U.S. Pat. No. 3,308,094. The useof tetramethylguanidine as a tertiary amine with a very low catalyticactivity is also mentioned in U.S. Pat. No. 6,743,375 in column 19. U.S.Pat. No. 6,743,375, however, teaches the skilled worker thattetramethylguanidine is a comparatively slow accelerant. A blend inwhich the hardener component a) is used in the range from 0.3 to 0.9amine equivalent per equivalent of epoxide of the epoxy resin used andthe hardener component b) is a compound of the formula I is notdescribed, however.

Among the technologies employing the curing of epoxides with amines areinfusion technologies. In these cases, diepoxy and polyepoxy resins aremixed with amines and polyetheramines immediately prior to the infusionprocedure, to form the blend, the blend is drawn into the respectivemold under suction, at temperatures of 20° C.-50° C., and issubsequently reacted at molding temperatures of 55° C.-90° C., and theblend is cured as a result. The rate of the overall process is dependenton the duration of the infusion step itself and on the duration ofcuring. The lower the viscosity of the blend, the quicker the infusionprocedure may take place. Reducing the viscosity of a given blend can beaccomplished by raising the temperature in the course of the infusionprocedure, thereby in principle making it quicker. Raising thetemperature during the infusion procedure for the purpose of reducingthe viscosity makes sense, however, only with amines of low reactivity,such as polyetheramines, for example. The disadvantage of the sole useof amines of low reactivity, such as polyetheramines, for example, isthe slow reaction of this component with the epoxy resin, as a result ofwhich the curing procedure is slow. The duration of curing can beshortened through the use of particularly reactive amines such as IPDA,for example. Where these reactive amines are present, however, infusionmust take place at low temperatures, since the viscosity of a mixture ofpolyetheramine and IPDA at temperatures>40° C. rises so rapidly that itis no longer possible to ensure complete impregnation of the fiber mats.

In the use of infusion technologies such as vacuum assisted resintransfer molding (VARTM) technology for the production of largecomponents, a long pot life on the part of the blend comprising epoxyresins and amines, in the region of several hours at room temperature,may be necessary in order to ensure a trouble-free infusion procedure.This long pot life can be achieved through the use of polyetheramines oflow reactivity, as are described in WO-A 2004/020506, pages 14-17. Inthe state of the art for infusion technology, the exclusive use ofactive hardeners such as IPDA is unknown for large components. Thedisadvantage of the use exclusively of polyetheramines of low reactivityin infusion technology lies in the extremely long cure times at elevatedtemperature, which prevent productivity increase and at the same timenecessitate increased employment of energy.

Improvement in the infusion process with blends comprising epoxy resinsand amines occurs when the viscosity of the blend during the infusionprocedure is low, or when, as a result of a relatively long pot life onthe part of the improved blend, the infusion procedure is able to takeplace at higher temperatures, and hence at a lower viscosity, than isthe case for the existing blends of epoxy resins, polyetheramines, andIPDA. The object of an improved process for producing such moldingswould be that of exhibiting a comparable or higher cure rate relative tothe prior art at temperatures of, for example, 60° C. or more.

Such processes would specifically be very suitable for the manufactureof large components, since, with a comparable or shorter cure rate, theprocessing time at room temperature would be prolonged, or processingwould be possible at higher temperatures, without premature curing ofthe blend, and hence complete and uniform curing would be enabled.

It is an object of the present invention, therefore, to provide a blendwhich allows the cure rate of the blend to be raised without at the sametime increasing the viscosity of the blend during processing in such away that complete filling of the mold and, if appropriate, uniformimpregnation of existing fiber material is no longer possible.

This object is achieved by means of a blend comprising

-   α) one or more epoxy resins and-   β) a mixture comprising    -   1) 0.3 to 0.9 amine equivalent, per equivalent of epoxide of        component α) used, of a hardener component a) and    -   2) a hardener component b),        -   wherein the hardener component a) comprises one or more            amines having a functionality≧2, and at least one amine,            when mixed stoichiometrically with the epoxy resin in the            100 g batch, leads at room temperature to a cure time of            less than 24 h, and the hardener component b) comprises at            least one compound of the formula I

where R1 to R3, R5 and R6 each independently are an organic radicalhaving 1 to 20 C atoms and hydrogen, and R4 is selected from the groupof an organic radical having 1 to 20 C atoms and a group —C(NH)NR5R6.

Advantageous is the blend of the invention wherein the hardenercomponent a) is selected from the group of amines having afunctionality≧2.

Advantageous is the blend of the invention wherein the hardenercomponent a) comprises at least two hardener components a1) and a2), thehardener component a1) being at least one polyetheramine having afunctionality≧2 and the hardener component a2) being at least onefurther amine having a functionality≧2.

Advantageous is the blend of the invention wherein

-   the hardener component a1) is selected from the group of    3,6-dioxa-1,8-octanediamine, 4,7,10-trioxa-1,13-tridecanediamine,    4,7-dioxa-1,10-decanediamine, 4,9-dioxa-1,12-dodecanediamine,    polyetheramine based on triethylene glycol with an average molar    mass of 148, difunctional, primary polyetheramine prepared by    aminating an ethylene glycol grafted with propylene oxide, with an    average molar mass of 176, difunctional, primary polyetheramine    based on propylene oxide with an average molar mass of 4000,    difunctional, primary polyetheramine prepared by aminating a    polyethylene glycol grafted with propylene oxide, with an average    molar mass of 2003, aliphatic polyetheramine based on polyethylene    glycol grafted with propylene oxide, with an average molar mass of    900, aliphatic polyetheramine based on polyethylene glycol grafted    with propylene oxide, with an average molar mass of 600,    difunctional, primary polyetheramine prepared by aminating a    diethylene glycol grafted with propylene oxide, with an average    molar mass of 220, aliphatic polyetheramine based on a copolymer of    poly(tetramethylene ether glycol) and polypropylene glycol with an    average molar mass of 1000, aliphatic polyetheramine based on a    copolymer of poly(tetramethylene ether glycol) and polypropylene    glycol with an average molar mass of 1900, aliphatic polyetheramine    based on a copolymer of poly(tetramethylene ether glycol) and    polypropylene glycol with an average molar mass of 1400,    polyethertriamine based on an at least trihydric alcohol grafted    with butylene oxide, with an average molar mass of 400, aliphatic    polyetheramine prepared by aminating alcohols grafted with butylene    oxide, with an average molar mass of 219, polyetheramine based on    pentaerythritol and propylene oxide with an average molar mass of    600, difunctional, primary polyetheramine based on polypropylene    glycol with an average molar mass of 2000, difunctional, primary    polyetheramine based on polypropylene glycol with an average molar    mass of 230, difunctional, primary polyetheramine based on    polypropylene glycol with an average molar mass of 400,    trifunctional, primary polyetheramine prepared by reacting propylene    oxide with trimethylolpropane, followed by amination of the terminal    OH groups, with an average molar mass of 403, trifunctional, primary    polyetheramine prepared by reacting propylene oxide with glycerol,    followed by amination of the terminal OH groups, with an average    molar mass of 5000, and a polyetheramine having an average molar    mass of 400, prepared by aminating polyTHF which has an average    molar mass of 250, and-   the hardener component a2) is selected from the group of    1,12-diaminododecane, 1,10-diaminodecane, 1,2-diaminocyclohexane,    1,2-propanediamine, 1,3-bis(aminomethyl)cyclohexane,    1,3-propanediamine, 1-methyl-2,4-diaminocyclohexane,    2,2′-oxybis(ethylamine),    3,3′-dimethyl-4,4′-diaminodicyclohexylmethane,    4,4′-methylenedianiline, 4-ethyl-4-methylamino-1-octylamine,    diethylenetriamine, ethylenediamine, hexamethylenediamine,    isophoronediamine, menthenediamine, xylylenediamine,    N-aminoethylpiperazine, neopentanediamine, norbornanediamine,    octamethylenediamine, piperazine,    4,8-diaminotricyclo[5.2.1.0]decane, tolylenediamine,    triethylenetetramine, and trimethylhexamethylenediamine.

Advantageous is the blend of the invention wherein the radicals R1 toR3, R5, and R6 of the compounds of the formula I are each independentlyselected from the group of hydrogen, methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, phenyl, and o-tolyl, and R4 is selected from thegroup of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, phenyl,o-tolyl, and a group —C(NH)NR5R6-.

Advantageous is the blend of the invention wherein the fraction ofhardener component b), based on the weight fraction of the mixture, is5% to 55% by weight.

Advantageous is the blend of the invention wherein the mixture comprisesas hardener component a1) a polyetheramine having a functionality of z2, selected from the group of difunctional, primary polyetheramine basedon polypropylene glycol, with an average molar mass of 230,difunctional, primary polyetheramine based on polypropylene glycol, withan average molar mass of 400, aliphatic, difunctional, primarypolyetheramine based on polypropylene glycol, with an average molar massof 2000, difunctional, primary polyetheramine prepared by aminating adiethylene glycol grafted with propylene oxide, with an average molarmass of 220, trifunctional, primary polyetheramine prepared by reactingpropylene oxide with trimethylolpropane, followed by amination of theterminal OH groups, with an average molar mass of 403, aliphaticpolyetheramine based on polyethylene glycol grafted with propyleneoxide, with an average molar mass of 900, aliphatic polyetheramine basedon a copolymer of poly(tetramethylene ether glycol) and polypropyleneglycol, with an average molar mass of 1000, aliphatic polyetheraminebased on a copolymer of poly(tetramethylene ether glycol) andpolypropylene glycol, with an average molar mass of 1900, aliphaticpolyetheramine based on a copolymer of poly(tetramethylene ether glycol)and polypropylene glycol, with an average molar mass of 1400,polyethertriamine based on an at least trihydric alcohol grafted withbutylene oxide, with an average molar mass of 400, aliphaticpolyetheramine prepared by aminating alcohols grafted with butyleneoxide, with an average molar mass of 219, trifunctional, primarypolyetheramine prepared by reacting propylene oxide with glycerol,followed by amination of the terminal OH groups, with an average molarmass of 5000, and as hardener component a2) a further amine having afunctionality≧2, selected from the group of isophoronediamine,aminoethylpiperazine, 1,3 bis(aminoethyl)cyclohexane, andtriethylenetetramine, the ratio of a1) to a2) being in the range from0.1 to 10:1.

Advantageous is the blend of the invention wherein the mixture comprisesas hardener component a1) a polyetheramine selected from the group ofpolyetheramine D 230, polyetheramine D 400, polyetheramine T 403,polyetheramine T 5000, the hardener component a2) is selected from thegroup of isophoronediamine, aminoethylpiperazine,1,3-bis(aminomethyl)cyclohexane, and triethylenetetraamine, and thehardener component b) is tetramethylguanidine, and the ratio of hardenercomponent a1) to hardener component a2) is in the range from 1.5 to10:1, and 10 to 60 mol % less of mixture is added to the epoxy resinthan is needed for the reaction of the active epoxy groups at aminefunctions of the mixture.

Advantageous is the blend of the invention wherein the blend furthercomprises fiber-reinforced material.

The invention further provides a process for preparing the blend of theinvention, which comprises mixing one or more epoxy resins with themixture at temperatures below the initial curing temperature of thehardener component a).

Further provided by the invention is the use of the blend of theinvention for producing cured epoxy resins.

Advantageous is the inventive use wherein the cured epoxy resins aremoldings.

Advantageous is the inventive use wherein the moldings comprisereinforcing material.

The invention further provides a cured epoxy resin obtainable by curingthe blend of the invention.

Advantageous is the cured epoxy resin of the invention wherein the curedepoxy resin is a molding.

The invention further provides a molding which is fiber-reinforced.

Advantageous is the molding of the invention obtainable by curing a moldlined with a fiber-reinforced material, and introducing the blend of theinvention into the mold by means of infusion technology.

Advantageous is the molding of the invention which constitutesreinforced components for rotor blades of wind turbines.

BRIEF DESCRIPTION OF THE FIGURES

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a graph showing glass transition temperature as a function ofcomposition.

FIG. 2 is a graph showing flexural strength as a function ofcomposition.

FIG. 3 is a 3D graph showing the relationship between vitrificationtime, percent TMG, and percent aminic curing.

The blends of the invention comprise at least one and/or two or moreepoxy resins and a mixture of a hardener component a) and a hardenercomponent b). The epoxy resins and/or epoxy resin mixtures for usepreferably comprise epoxy resins selected from the group of bisphenol Abisglycidyl ether (DGEBA), bisphenol F bisglycidyl ether, bisphenol Sbisglycidyl ether (DGEBS), tetraglycidylmethylenedianilines (TGMDA),epoxy novolaks (the reaction products of epichlorohydrin and phenolicresins (novolak)), and cycloaliphatic epoxy resins such as3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and diglycidylhexahydrophthalate.

Moreover the epoxy resins may also comprise further reactive diluents.These diluents are selected from the group of 1,4-butanediol bisglycidylether, 1,6-hexanediol bisglycidyl ether, glycidyl neodecanoate, glycidylversatate, 2-ethylhexyl glycidyl ether, C₈-C₁₀ alkyl glycidyl ethers,C₁₂-C₁₄ alkyl glycidyl ethers, p-tert-butyl glycidyl ether, butylglycidyl ether, nonylphenyl glycidyl ether, p-tert-butylphenyl glycidylether, phenyl glycidyl ether, o-cresyl glycidyl ether, polyoxypropyleneglycol diglycidyl ether, trimethylolpropane triglycidyl ether (TMP),glycerol triglycidyl ether, and triglycidyl-para-aminophenol (TGPAP).

In accordance with the prior art a virtually stoichiometric amount isused for the curing of epoxy resins (depending on epoxy resin, 0.9-1.1equivalents of the hardener/equivalent of epoxy resin). If, however, themixture of the invention is used for curing epoxy resins, it ispreferred to add 10 to 60 mol %, more preferably 20 to 40 mol %, less ofthe inventive mixture to the epoxy resin than needed for the reaction ofthe active epoxy groups at amine functions of the mixture. It isparticularly preferred if, in total, 0.3 to 0.9 amine equivalent,preferably 0.4 to 0.7 amine equivalent, per epoxide equivalent of theepoxy resin used, of hardener components a1) and a2) is added to themixture in order to obtain an increase in the pot life and a comparableor improved curing of the epoxy resin as compared with the mixtures ofthe prior art. For the blend of the invention the fraction of thehardener component a) is 0.3 to 0.9, preferably 0.4 to 0.7, amineequivalent per epoxide equivalent of the epoxy resin used.

For preparing the blend of the invention and for the process of theinvention, the mixture is mixed with the epoxy resin at temperaturesbelow the initial curing temperature of the hardener component a). Theinitial curing temperature is the temperature at which, in a mixture oftwo or more hardener components having a functionality≧2, the firsthardener component reacts with the epoxy resin. This temperature can bedetermined by a DSC in accordance with DIN 53765 as T_(RO) ^(E).

The hardener component a) in the blend of the invention, and also forthe process of the invention, comprises one or more amines having afunctionality≧2, at least one amine, when mixed stoichiometrically withthe epoxy resin in the 100 g batch, leading at room temperature to acure time of less than 24 h.

The amines having a functionality≧2 of hardener component a) are allamines known to the skilled worker and having a functionality≧2.Preferably they are selected from the group of3,6-dioxa-1,8-octanediamine, 4,7,10-trioxa-1,13-tridecanediamine,4,7-dioxa-1,10-decanediamine, 4,9-dioxa-1,12-dodecanediamine,polyetheramine based on triethylene glycol with an average molar mass of148, difunctional, primary polyetheramine prepared by aminating anethylene glycol grafted with propylene oxide, with an average molar massof 176, difunctional, primary polyetheramine based on propylene oxidewith an average molar mass of 4000, difunctional, primary polyetheramineprepared by aminating a polyethylene glycol grafted with propyleneoxide, with an average molar mass of 2003, aliphatic polyetheraminebased on polyethylene glycol grafted with propylene oxide, with anaverage molar mass of 900, aliphatic polyetheramine based onpolyethylene glycol grafted with propylene oxide, with an average molarmass of 600, difunctional, primary polyetheramine prepared by aminatinga diethylene glycol grafted with propylene oxide, with an average molarmass of 220, aliphatic polyetheramine based on a copolymer ofpoly(tetramethylene ether glycol) and polypropylene glycol with anaverage molar mass of 1000, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1900, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1400, polyethertriamine based on an atleast trihydric alcohol grafted with butylene oxide, with an averagemolar mass of 400, aliphatic polyetheramine prepared by aminatingalcohols grafted with butylene oxide, with an average molar mass of 219,polyetheramine based on pentaerythritol and propylene oxide with anaverage molar mass of 600, difunctional, primary polyetheramine based onpolypropylene glycol with an average molar mass of 2000, difunctional,primary polyetheramine based on polypropylene glycol with an averagemolar mass of 230, difunctional, primary polyetheramine based onpolypropylene glycol with an average molar mass of 400, trifunctional,primary polyetheramine prepared by reacting propylene oxide withtrimethylolpropane, followed by amination of the terminal OH groups,with an average molar mass of 403, trifunctional, primary polyetheramineprepared by reacting propylene oxide with glycerol, followed byamination of the terminal OH groups, with an average molar mass of 5000,and a polyetheramine having an average molar mass of 400, prepared byaminating polyTHF which has an average molar mass of 250,1,12-diaminododecane, 1,10-diaminodecane, 1,2-diaminocyclohexane,1,2-propanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,3-propanediamine,1-methyl-2,4-diaminocyclohexane, 2,2′-oxybis(ethylamine),3,3′-dimethyl-4,4′-diaminodicyclohexylmethane,4-ethyl-4-methylamino-1-octylamine, diethylenetriamine, ethylenediamine,hexamethylenediamine, isophoronediamine, menthenediamine,xylylenediamine, N-aminoethylpiperazine, neopentanediamine,norbornanediamine, octamethylenediamine, piperazine,4,8-diaminotricyclo[5.2.1.0]decane, tolylenediamine,triethylenetetramine, and trimethyihexamethylenediamine.

With particular preference the hardener component a) comprises at leasttwo hardener components a1) and a2), with both comprising an aminehaving a functionality≧2. With very particular preference the hardenercomponent a1) comprises a polyetheramine and the hardener component a2)comprises a further amine having a functionality≧2.

Polyamines with oxygen in their chain are referred to aspolyetheramines.

Polyetheramines having a functionality of ≧2 can be used in the blend ofthe invention and in the process of the invention as hardener componenta), and in the mixture of the invention as hardener component a1). Theycan be prepared inter alia on the basis of alkylene oxides such asethylene oxide, propylene oxide, butylene oxide or pentylene oxide,polyTHF or 1,4-butanediol and in each case ammonia, and have molarweight distributions. The alkylene oxides used may be the same ordifferent per molecule. The polyetheramines of types D, ED, and EDR arediamines (D type), with ED standing for diamine based on polyethyleneglycol (PEG) and EDR standing for reactive diamines based on PEG; the Ttypes are a triol which is grafted with alkylene oxide(s) and whichcarries an amino group on each of the three termini. XTJ is used forproducts still intended for trial. The numbers after the letter code,except for the XTJ products, in the name of the polyetheramines givesthe average molar mass of the polyetheramine. The polyetheramines usedin the mixture of the invention, in the blend of the invention, and inthe process of the invention have a functionality of 2.

Typical examples of polyetheramines of hardener component a1) areselected from the group of difunctional, primary polyetheramine based onpolypropylene glycol, with an average molar mass of 230, difunctional,primary polyetheramine based on polypropylene glycol, with an averagemolar mass of 400, difunctional, primary polyetheramine based onpolypropylene glycol, with an average molar mass of 2000, difunctional,primary polyetheramines based on propylene oxide, with an average molarmass of 4000, trifunctional, primary polyetheramine prepared by reactingpropylene oxide with trimethylolpropane, followed by amination of theterminal OH groups, with an average molar mass of 403, trifunctional,primary polyetheramine prepared by reacting propylene oxide withglycerol, followed by amination of the terminal OH groups, with anaverage molar mass of 5000. These compounds are also sales products ofthe companies BASF (Polyetheramines) and Huntsman (Jeffamines) and areavailable under the following tradenames:

Polyetheramine D 230/Jeffamine® D 230:

comprises polyetheramine based on polypropylene glycol with an averagemolar mass of 230.

Polyetheramine D 400/Jeffamine® XTJ 582:

comprises difunctional, primary polyetheramine based on polypropyleneglycol with an average molar mass of 400.

Polyetheramine D 2000/Jeffamine® D2000/Jeffamine® XTJ 578:

comprises aliphatic, difunctional, primary polyetheramine based onpolypropylene glycol with an average molar mass of 2000.

Polyetheramine D 4000:

comprises polyetheramines based on polypropylene glycol with an averagemolar mass of 4000.

Polyetheramine T 403/Jeffamine® T 403:

comprises polyetheramine prepared by reacting propylene oxide withtrimethylolpropane, followed by amination of the terminal OH groups,with an average molar mass of 403.

Polyetheramine T 5000/Jeffamine® T 5000:

comprises polyetheramine prepared by reacting propylene oxide withglycerol, followed by amination of the terminal OH groups, with anaverage molar mass of 5000.

Jeffamine® ED-600/Jeffamine® XTJ 501:

comprises an aliphatic polyetheramine constructed from a polyethyleneglycol grafted with propylene oxide, and having an average molar mass of600.

Jeffamine® ED-900:

comprises an aliphatic polyetheramine constructed from a polyethyleneglycol grafted with propylene oxide, and having an average molar mass of900.

Jeffamine® ED-2003:

comprises an aliphatic polyetheramine constructed from a polyethyleneglycol grafted with propylene oxide, and having an average molar mass of2000.

Jeffamine® HK-511:

comprises a difunctional, primary polyetheramine prepared by aminating adiethylene glycol grafted with propylene oxide, with an average molarmass of 220.

Jeffamine® XTJ-542:

comprises an aliphatic polyetheramine based on a copolymer ofpoly(tetramethylene ether glycol) and polypropylene glycol, with anaverage molar mass of 1000.

Jeffamine® XTJ-548:

comprises an aliphatic polyetheramine based on a copolymer ofpoly(tetramethylene ether glycol) and polypropylene glycol, with anaverage molar mass of 1900.

Jeffamine® XTJ-559:

comprises copolymers of poly(tetramethylene ether glycol) andpolypropylene glycol with an average molar mass of 1400.

Jeffamine® XTJ-566:

comprises polyethertriamine based on an at least trihydric alcoholgrafted with butylene oxide, with an average molar mass of 400.

Jeffamine® XTJ-568:

comprises an aliphatic polyetheramine prepared by aminating alcoholsgrafted with butylene oxide, with an average molar mass of 219.

Jeffamine® XTJ-616:

comprises a polyetheramine based on pentaerythritol and propylene oxidewith an average molar mass of 600.

Jeffamine® EDR-148:

comprises a polyetheramine based on triethylene glycol with an averagemolar mass of 148.

Jeffamine® EDR-176:

comprises a difunctional, primary polyetheramine prepared by aminatingan ethylene glycol grafted with propylene oxide, with an average molarmass of 176.

PoLyTHF-Amine 350:

comprises a polyetheramine prepared by aminating polyTHF with an averagemolar mass of 250. The resultant polyTHF-amine possesses an averagemolecular weight of 400.

The polyetheramines of hardener component a1) are preferably selectedfrom the group of difunctional, primary polyetheramine prepared byaminating diethylene glycol, grafted with propylene oxide, with anaverage molar mass of 220, aliphatic polyetheramine based onpolyethylene glycol grafted with propylene oxide, with an average molarmass of 900, aliphatic polyetheramine based on a copolymer ofpoly(tetramethylene ether glycol) and polypropylene glycol with anaverage molar mass of 1000, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1900, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1400, polyethertriamine based on an atleast trihydric alcohol grafted with butylene oxide, with an averagemolar mass of 400, aliphatic polyetheramine prepared by aminatingalcohols grafted with butylene oxide, with an average molar mass of 219,difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 230, difunctional, primary polyetheramine basedon polypropylene glycol with an average molar mass of 400,trifunctional, primary polyetheramine prepared by reacting propyleneoxide with trimethylolpropane, followed by amination of the terminal OHgroups, with an average molar mass of 403, and a polyetheramine based onpropylene oxide and glycerol with an average molar mass of 5000. A veryparticularly preferred polyetheramine is a polyetheramine based onpolypropylene glycol with an average molar mass of 230, such aspolyetheramine D 230 or Jeffamine® D230, for example.

Hardener components a2) used are further amines having afunctionality≧2, selected from the group of 1,12-diaminododecane,1,10-diaminodecane, 1,2-diaminocyclohexane, 1,2-propanediamine,1,3-bis(aminomethyl)cyclohexane, 1,3-propanediamine,1-methyl-2,4-diaminocyclohexane, 2,2′-oxybis(ethylamine),3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, 4,4′-methylenedianiline,4-ethyl-4-methylamino-1-octylamine, diethylenetriamine, ethylenediamine,hexamethylenediamine, isophoronediamine, menthenediamine,xylylenediamine, N-aminoethylpiperazine, neopentanediamine,norbornanediamine, octamethylenediamine, piperazine4,8-diaminotricyclo[5.2.1.0]-decane, tolylenediamine,triethylenetetramine, and trimethylhexamethylenediamine.

In the mixture of the invention, the blend of the invention and also inthe process of the invention there may also be accelerants present aswell. These are selected from the group of substituted imidazoles suchas 1-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole,2-phenylimidazole, 1-cyanoethylimidazole, imidazolines such as2-phenylimidazoline, tertiary amines such as N,N-dimethylbenzylamine,2,4,6-tris(dimethylaminomethyl)phenol (DMP 30), bisphenol A, bisphenolF, nonyl-phenol, p-tert-butylphenol, phenolic resins of the novolaktype, salicylic acid, p-toluene-sulfonic acid,1,4-diazabicyclo[2.2.2]octane (DABCO),1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), S-triazine (Lupragen N 600),bis(2-dimethylaminoethyl) ether (Lupragen N 206),pentamethyldiethylenetriamine (Lupragen N 301),trimethylaminoethylethanol-amine (Lupragen N 400),tetramethyl-1,6-hexanediamine (Lupragen N 500), amino-ethylmorpholine,aminopropylmorpholine, aminoethylethyleneurea, ketimines such asEpi-Kure 3502 (a reaction product of ethylenediamine with methylisobutyl ketone), urons such as 3-(4-chlorophenyl)-1,1-dimethylurea(Monuron), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (Diuron),3-phenyl-1,1-dimethylurea (Fenuron), and3-(3-chloro-4-methylphenyl)-1,1-dimethylurea (Chlorotoluron), tolyl-2,4bis-N,N-dimethylcarbamide (Amicure UR2T), dicyandiamide (DICY), Mannichbases or secondary amines such as dialkylamines, such asdi(2-ethylhexyl)amine, dibutylamine, dipropylamine, ditridecyl-amine,N,N′-diisopropylisophoronediamine (Jefflink® XTJ-584),N,N′-diisobutyl-4,4″-diaminodicyclohexylmethane (Clearlink 1000),N-(hydroxyethyl)aniline, and di(2-methoxyethyl)amine, for example.

In addition to the hardener component a) or a1) and a2), the mixture ofthe invention, the blend of the invention and the process of theinvention further comprise a hardener component b) of the formula I

The radicals R1 to R3, R5, and R6 of the formula I in the hardenercomponent b) of the mixture of the invention, of the blend of theinvention and also of the process of the invention are eachindependently selected from the group of an organic radical having 1 to20 C atoms and hydrogen. Organic radical means all saturated,unsaturated, cyclic or acyclic hydrocarbon radicals which carry noheteroatoms. With particular preference the organic radical has 1 to 10C atoms.

Organic radicals which are unsaturated and cyclic include aromaticgroups. Preferred aromatic hydrocarbon radicals are selected from thegroup of phenyl, benzyl, xylene, o-tolyl, a phenyl group substituted byone or more C₂ to C₄ alkyl groups, and benzyl group. Particularlypreferred aromatic hydrocarbon radicals are phenyl groups.

The aliphatic hydrocarbon radicals are selected from the group of cyclicand acyclic hydrocarbon radicals. The acyclic aliphatic hydrocarbonradicals are preferred. In this case it is possible with preference, ashydrocarbon radicals, to use those with C₁ to C₁₀ atoms, more preferablyC₁ to C₄ atoms.

With very particular preference the radicals for R1 to R3, R5, and R6are selected from the group of methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, phenyl, and o-tolyl radicals. With very particularpreference more particularly, the radicals selected for the radicals R1to R3, R5 and R6 are the aliphatic hydrocarbon radicals selected fromthe group of methyl, ethyl, n-propyl, isopropyl, n-butyl or sec-butylgroup. With very particular preference more particularly are methyl,ethyl, n-propyl, and n-butyl group.

R4, for the mixture of the invention, the blend of the invention and theprocess of the invention, is selected, independently of R1 to R3, R5,and R6, from the group of an organic radical having 1 to 20 C atoms anda group —C(NH)NR5R6-. With particular preference R4 is selected from thegroup of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, phenyland o-tolyl radical. With very particular preference more particularlyare methyl, ethyl, n-propyl, n-butyl, and o-tolyl radical.

In one particularly preferred embodiment R1 to R4 independently of oneanother are organic aliphatic hydrocarbons selected from the group ofmethyl, ethyl, n-propyl, isopropyl, n-butyl, and sec-butyl radical. Withvery particular preference more particularly are methyl, ethyl,n-propyl, and n-butyl group.

With very particular preference more particularly the compound offormula I is tetramethylguanidine.

The fraction of the compound of the formula I in the blend of theinvention and in the process of the invention is situated in the rangefrom 0.5% to 25% by weight, based on the amount of epoxy resin used.

The fraction of the formula I in the mixture of the invention issituated in the range from 5% to 55%, preferably in the range from 5% to30%, more preferably between 10% and 25%, by weight, based on the amountof the mixture.

Preferred mixtures of the invention and also blends of the invention arethose which in addition to tetramethylguanidine also, additionally,comprise polyetheramines selected from the group of3,6-dioxa-1,8-octanediamine, 4,7,10-trioxa-1,13-tridecanediamine,4,7-dioxa-1,10-decanediamine, 4,9-dioxa-1,12-dodecanediamine,difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 2000, such as, for example, Jeffamine® D-2000,Jeffamine® XTJ-578 and Polyetheramine D 2000, difunctional, primarypolyetheramine based on polypropylene glycol with an average molar massof 230, such as, for example, Jeffamine® D-230 and Polyetheramine D 230,difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 400, such as, for example, Jeffamine® D-400,Jeffamine® XTJ-582 and Polyetheramine D 400, difunctional, primarypolyetheramine based on propylene oxide with an average molar mass of4000, such as, for example, Jeffamine® D-4000, difunctional, primarypolyetheramine prepared by aminating a polyethylene glycol grafted withpropylene oxide, with an average molar mass of 2003, such as, forexample, Jeffamine® ED-2003, aliphatic polyetheramine based onpolyethylene glycol grafted with propylene oxide, with an average molarmass of 900, such as, for example, Jeffamine® ED-900, aliphaticpolyetheramine based on polyethylene glycol grafted with propyleneoxide, with an average molar mass of 2000, such as, for example,Jeffamine® ED-2003, aliphatic polyetheramine based on polyethyleneglycol grafted with propylene oxide, with an average molar mass of 600,such as, for example, Jeffamine® ED-600 and Jeffamine® XTJ 501,difunctional, primary polyetheramine prepared by aminating a diethyleneglycol grafted with propylene oxide, with an average molar mass of 220,such as, for example, Jeffamine® HK-511, trifunctional, primarypolyetheramine prepared by reacting propylene oxide withtrimethylolpropane, followed by amination of the terminal OH groups,with an average molar mass of 403, such as, for example, Jeffamine®T-403 and Polyetheramine T 403, trifunctional, primary polyetheramineprepared by reacting propylene oxide with glycerol, followed byamination of the terminal OH groups, with an average molar mass of 5000,such as, for example, Jeffamine® T-5000 and Polyetheramine T 5000,aliphatic polyetheramine based on a copolymer of poly(tetramethyleneether glycol) and polypropylene glycol with an average molar mass of1000, such as, for example, Jeffamine® XTJ-542, aliphatic polyetheraminebased on a copolymer of poly(tetramethylene ether glycol) andpolypropylene glycol with an average molar mass of 1900, such as, forexample, Jeffamine® XTJ-548, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1400, such as, for example, Jeffamine®XTJ-559, aliphatic polyethertriamine based on an at least trihydricalcohol grafted with butylene oxide, with an average molar mass of 400,such as, for example, Jeffamine® XTJ-566, aliphatic polyetheramineprepared by aminating alcohols grafted with butylene oxide, with anaverage molar mass of 219, such as, for example, Jeffamine® XTJ-568,polyetheramine based on pentaerythritol and propylene oxide with anaverage molar mass of 600, such as, for example, Jeffamine® XTJ-616,polyetheramine based on triethylene glycol with an average molar mass of148, such as, for example, Jeffamine® EDR 148, difunctional, primarypolyetheramine prepared by aminating an ethylene glycol grafted withpropylene oxide, with an average molar mass of 176, such as, forexample, Jeffamine® EDR 176, and a polyetheramine having an averagemolar mass of 400, prepared by aminating polyTHF with an average molarmass of 250, such as polyTHF Amine 350, for example.

Particularly preferred mixtures of the invention and also blends of theinvention are firstly those which besides tetramethylguanidine andpolyetheramines selected from the group of difunctional, primarypolyetheramine based on polypropylene glycol with an average molar massof 230, such as, for example, Jeffamine® D-230 and Polyetheramine D 230,difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 400, such as, for example, Jeffamine® D-400,Jeffamine® XTJ-582, and Polyetheramine D 400, difunctional, primarypolyetheramine prepared by aminating a diethylene glycol grafted withpropylene oxide, with an average molar mass of 220, such as, forexample, Jeffamine® HK-511, trifunctional, primary polyetheramineprepared by reacting propylene oxide with trimethylolpropane, followedby amination of the terminal OH groups, with an average molar mass of403, such as, for example, Jeffamine® T-403 and Polyetheramine T 403,aliphatic polyetheramine based on polyethylene glycol grafted withpropylene oxide, with an average molar mass of 900, such as, forexample, Jeffamine® ED-900, aliphatic polyetheramine based on acopolymer of poly(tetramethylene ether glycol) and polypropylene glycolwith an average molar mass of 1000, such as, for example, Jeffamine®XTJ-542, polyetheramine based on a copolymer of poly(tetramethyleneether glycol) and polypropylene glycol with an average molar mass of1900, such as, for example, Jeffamine® XTJ-548, aliphatic polyetheraminebased on a copolymer of poly(tetramethylene ether glycol) andpolypropylene glycol with an average molar mass of 1400, such as, forexample, Jeffamine® XTJ-559, aliphatic polyethertriamine based on an atleast trihydric alcohol grafted with butylene oxide, with an averagemolar mass of 400, such as, for example, Jeffamine® XTJ-566, aliphaticpolyetheramine prepared by aminating alcohols grafted with butyleneoxide, with an average molar mass of 219, such as, for example,Jeffamine® XTJ-568, also, additionally, comprise a diamine selected fromthe group of isophoronediamine, 1,2-diaminocyclohexane,1-methyl-2,4-diaminocyclohexane, and 1,3-bis(aminomethyl)cyclohexane. Avery particularly preferred mixture of the invention is the mixturecomprising tetramethylguanidine, difunctional primary polyetheraminebased on polypropylene glycol with an average molar mass of 230, suchas, for example, Jeffamine® D-230 and Polyetheramine D 230 andisophoronediamine.

In the case of a mixture of the invention and of a preferred blend ofthe invention in which, in addition to the compound of the formula I, apolyetheramine and a further amine having a functionality≧2 are used,the polyetheramine is present in a ratio with respect to the furtheramine in the range from 0.1 to 10:1, preferably in the range from 1.5 to10:1, more preferably in the range from 2.0 to 5.0:1. In an especiallypreferred mixture of the invention and a more particularly especiallypreferred blend comprising tetramethylguanidine, PolyetheramineD230/Jeffamine® D230, and isophoronediamine, the preferred mixing ratioof Polyetheramine D230/Jeffamine® D230 to isophoronediamine is in therange from 2.2 to 2.6:1, more preferably in the range from 2.3 to 2.5:1.

The mixture of the invention is mixed from the individual constituentsby mechanical methods known to the skilled worker at temperatures below160° C., preferably in the range from 5 to 30° C.

When the mixture of the invention is utilized to cure epoxy resins, therate of curing is comparable or better in relation to curing systemsfrom the prior art.

Besides the use of the mixture of the invention in infusion technologiessuch as, for example, resin infusion, resin transfer molding (RTM),vacuum assisted resin transfer molding (VARTM), which are described inU.S. Pat. No. 3,379,591, the mixtures of the invention and blends of theinvention can also be employed for further technologies for the curingof epoxy resins that require a sufficient processing life attemperatures of 15-45° C. in combination with rapid curing at highertemperatures. These technologies are selected from the group of filamentwinding, pultrusion, hand lay-up and prepreg, as described in U.S. Pat.No. 3,379,591 and U.S. Pat. No. 5,470,517. In the hand lay-up process, afiber material is wetted manually or mechanically with epoxy resin andthen these mats are inserted into a mold and, where two or more layersare used, are consolidated with rollers or similar apparatus. Curingoften takes place in a vacuum bag, since this consolidates the materialand allows a precise epoxy resin content to be set.

The present invention further provides the cured epoxy resin obtainableby curing the blend of the invention or by curing an epoxy resin orepoxy resin mixture with the mixture of the invention. For this purposethe blends of the invention are either introduced into special molds orapplied to surfaces and induced to cure by an increase in temperature.The blends for application to surfaces may further comprise additionalfillers in the blends. These fillers are selected from the group ofthixotropic agents (hydrophilic and hydrophobic fumed silicas), UVstabilizers (nanoscale oxides such as titanium dioxide and zinc oxide),flame retardants (polyphosphates and phosphorus), silicates, andcarbonates for improving the mechanical properties. The molds that areused and into which the blends of the invention are introduced maycomprise fiber-reinforcing material or else may comprise elements whichare to be protected from environmental effects such as damp, oxygen,dust particles or other aggressive materials or influences.

Preferred cured epoxy resins are those which are cured in a molding.These moldings are selected from the group of moldings for motorvehicles, aircraft, ships, boats, sports goods, and blades for windturbines. Moldings for rotor blades of wind turbines are particularlypreferred.

The moldings may be lined either with or without a fiber-reinforcingmaterial, and/or else fiber-reinforcing materials may additionally beadded to the blend of the invention and/or to the mixture of theinvention. The fiber-reinforcing materials may therefore be wovenfabrics, uniaxial and multiaxial laid fabrics, nonwovens, and shortfibers of the following fiber materials: glass fibers, carbon fibers,aramid fibers, PE fibers (Dyneema), and basalt fibers. Preference isgiven to woven fabrics and to uniaxial and multiaxial lays of glassfibers and carbon fibers. In the case of large components which arefiber-reinforced, the components are preferably lined with thefiber-reinforcing material. Uniaxial and multiaxial lays of glass fibersare particularly preferred. The rotor shells for wind turbines arepreferably lined with laid glass fiber fabrics.

The moldings are produced preferably by the process of the invention, inwhich a corresponding mold is provided, the blend of the invention isintroduced into this mold, and the blend is cured to completion onlywhen the mold has been completely filled. In the case of the process ofthe invention, the blend of the invention, which may comprise themixture of the invention, is introduced into the corresponding moldpreferably by way of the infusion technology. In this case a vacuum isapplied to the molding. This vacuum draws the blend comprising epoxyresin and, if desired, the mixture of the invention into the mold undersuction at temperatures below the initial curing temperature, and so theviscosity during the filling operation remains virtually unchanged andall of the regions of the molding are filled by the blend before thelatter is fully cured. This is followed by complete curing of the blendin the molding. For complete curing it is possible to apply further heatsources from outside.

In the presence of epoxy resins, the mixture of the invention can alsobe used as a structural adhesive for composite components with oneanother and also with other materials of construction such as metals andconcrete. In this context the mixture of the invention or the blend ofthe invention can be combined with fibrous fillers such as short glassfibers and with fillers such as thixotropic agents (hydrophilic andhydrophobic fumed silicas), UV stabilizers (nanoscale oxides such astitanium dioxide and zinc oxide), flame retardants (polyphosphates andphosphorus), silicates and carbonates. In relation to the prior art, thestructural adhesives combine a long processing life with short curingtimes under the curing conditions specified above.

EXAMPLES

The state of the art selected was a mixture of Polyetheramine D230 andisophoronediamine in a weight ratio of 70/30.

The blend in which a mixture of Polyetheramine D230 andisophoronediamine and tetramethylguanidine is used comprises 82% byweight of commercial bisphenol A bisglycidyl ether (Epilox A19-03) and18% by weight of butanediol bisglycidyl ether (Epilox P13-21).

The mixtures of the invention for the curing of the epoxy resin systemare composed of mixtures of Polyetheramine D230 and Isophoronediamine(IPDA) at a constant weight ratio of 70/30, to whichtetramethylguanidine (TMG) is admixed in varying amounts. The overviewof the combinations tested is found in table 1.

TABLE 1 Composition of the combinations investigated Initial mass TestNo. Epoxy resin Polyetheramine Line/Column system D 230 IPDA TMG 1/138.71 g 7.90 g 3.39 g 0.00 g 1/2 38.26 g 7.81 g 3.35 g 0.59 g 1/3 37.77g 7.71 g 3.30 g 1.22 g 1/4 37.23 g 7.60 g 3.26 g 1.92 g 1/5 36.65 g 7.48g 3.20 g 2.67 g 1/6 35.30 g 7.20 g 3.09 g 4.41 g 2/2 39.18 g 7.20 g 3.08g 0.54 g 2/3 38.71 g 7.11 g 3.05 g 1.13 g 2/4 38.21 g 7.02 g 3.01 g 1.77g 2/5 37.65 g 6.91 g 2.96 g 2.47 g 2/6 36.37 g 6.68 g 2.86 g 4.09 g 3/240.15 g 6.55 g 2.81 g 0.49 g 3/3 39.71 g 6.48 g 2.78 g 1.03 g 3/4 39.24g 6.41 g 2.75 g 1.61 g 3/5 38.71 g 6.32 g 2.71 g 2.26 g 3/6 37.50 g 6.12g 2.62 g 3.75 g 4/2 41.16 g 5.88 g 2.52 g 0.44 g 4/3 40.76 g 5.82 g 2.50g 0.92 g 4/4 40.32 g 5.76 g 2.47 g 1.45 g 4/5 39.84 g 5.69 g 2.44 g 2.03g 4/6 38.71 g 5.53 g 2.37 g 3.39 g 5/2 42.23 g 5.17 g 2.22 g 0.39 g 5/341.86 g 5.13 g 2.20 g 0.81 g 5/4 41.47 g 5.08 g 2.18 g 1.28 g 5/5 41.03g 5.02 g 2.15 g 1.79 g 5/6 40.00 g 4.90 g 2.10 g 3.00 g 6/2 43.35 g 4.42g 1.90 g 0.33 g 6/3 43.03 g 4.39 g 1.88 g 0.70 g 6/4 42.68 g 4.35 g 1.87g 1.10 g 6/5 42.29 g 4.32 g 1.85 g 1.54 g 6/6 41.38 g 4.22 g 1.81 g 2.59g 7/2 44.53 g 3.64 g 1.56 g 0.27 g 7/3 44.26 g 3.61 g 1.55 g 0.57 g 7/443.97 g 3.59 g 1.54 g 0.90 g 7/5 43.64 g 3.56 g 1.53 g 1.27 g 7/6 42.86g 3.50 g 1.50 g 2.14 g 8/2 45.79 g 2.80 g 1.20 g 0.21 g 8/3 45.57 g 2.79g 1.20 g 0.44 g 8/4 45.34 g 2.78 g 1.19 g 0.70 g 8/5 45.07 g 2.76 g 1.18g 0.99 g 8/6 44.45 g 2.72 g 1.17 g 1.67 g 9/2 47.11 g 1.92 g 0.82 g 0.14g 9/3 46.96 g 1.92 g 0.82 g 0.30 g 9/4 46.79 g 1.91 g 0.82 g 0.48 g 9/546.60 g 1.90 g 0.82 g 0.68 g 9/6 46.16 g 1.88 g 0.81 g 1.15 g 10/2 48.51 g 0.99 g 0.42 g 0.07 g 10/3  48.43 g 0.99 g 0.42 g 0.16 g 10/4 48.34 g 0.99 g 0.42 g 0.25 g 10/5  48.24 g 0.98 g 0.42 g 0.35 g 10/6 48.00 g 0.98 g 0.42 g 0.60 g

The table below shows the results of the pot life determination bymethod B at 60° C.

TABLE 2 Determination of pot life by method B at 60° C. Pot lifedetermination by method B at 60° C. Parts by weight of TMG in themixture 0 5 10 15 20 30 Line Percent 100  75 min  80 min  85 min 100 min120 min 125 min 1 aminic 90  90 min  90 min 100 min 115 min 130 min 2curing 80 110 min 110 min 145 min 135 min 130 min 3 70 150 min 135 min140 min 140 min 155 min 4 60 170 min 160 min 140 min 140 min 135 min 550 195 min 185 min 165 min 160 min 155 min 6 40 270 min 220 min 190 min175 min 160 min 7 30 — 285 min 220 min 200 min 180 min 8 20 — — 290 min270 min 250 min 9 10 — — — — 330 min 10 Column 1 2 3 4 5 6

For the prior art a pot life (ToB) of 75 min was found.

The tests show (line 1) that the addition of TMG to a mixture ofPolyetheramines D230 and IPDA and the use of this blend of the inventionleads to an increase in the pot life. A fraction of 30% by weight of TMGin the mixture of the invention or the blend of the invention may raisethe pot life by around 66%.

Furthermore, the tests (column 3) show that a reduction in the fractionof the Polyetheramine D230 and of the IPDA (percent aminic curing) inthe range from 0.3 to 0.9 amine equivalent per epoxide equivalentresults in a more significant increase in the pot life than in the caseof the addition of TMG to a stoichiometric mixture of PolyetheramineD230 and IPDA. Thus for a combination of 30% of Polyetheramine D230 andIPDA (aminic curing) and 10% by weight of TMG in the mixture of theinvention, an increase in pot life by 380% is achieved.

In addition, the experiments show that the rate of curing betweeninventive examples and the comparative example is comparable or better.This effect can be demonstrated by determining the vitrification timefor a number of selected systems (1/1; 2/4; 3/2; 4/2; 5/3; 6/3; 6.4;7/4; 8/4; 9/6) (FIG. 3). The vitrification time was determined by meansof MDSC as the half-step height of the step-shaped transition of thespecific heat capacity. This method is described in the article“Understanding vitrification during cure of epoxy resins using dynamicscanning calorimetry and rheological techniques.” (Polymer, 41 (2000)5949 Ff).

The mixture according to the invention reduces the vitrification timefrom >6 hours to a time≦3 hours for a curing temperature of 70° C. incomparison to the prior art.

Since the composition of the mixture not only affects the reactivity butalso has consequences for other parameters such as glass transitiontemperature and mechanical characteristics, corresponding investigationswere carried out for the systems specified in table 1.

The glass transition temperature (FIG. 1) is depicted as a function ofthe composition. On the X-axes the fraction of the sum of PolyetheramineD230 and IPDA (aminic curing) (corresponding to lines) is shown, and onthe y-axes the weight fraction of the TMG (curing component b))(corresponding to columns) is shown. The color changes as a function ofthe glass transition temperature attained. White denotes high glasstransition temperature and black denotes low glass transitiontemperature.

The flexural strength (FIG. 2) is depicted as a function of thecomposition. Shown on the X-axes is the fraction of the sum ofPolyetheramine D230 and IPDA (aminic curing) (corresponding to lines)and on the y-axes the weight fraction of the TMG (hardener component b))(corresponding to columns) is shown. The color changes as a function ofthe flexural strength attained. White denotes high and black denotes lowflexural strength.

When all of these results are considered, the outcome is that themixture according to the invention represents an optimum combination ofall of the parameters: processing, cure time, and mechanical and thermalproperties.

The invention claimed is:
 1. A blend comprising α) one or more epoxyresins and β) a mixture comprising a) a hardener component comprisingone or more amines having a functionality≧2, wherein at least one ofsaid amines, when mixed stoichiometrically with the epoxy resin in a 100g batch, leads at room temperature to a cure time of less than 24 h; andb) a hardener component comprising at least one compound of formula I

provided in an amount of 5% to 55% by weight, based on the weight of themixture β) such that the at least one compound of formula I is providedin an amount of 5 to 30% by weight, based on the weight of the mixtureβ), wherein, R4 is selected from the group consisting of an organicradical having 1 to 20 C atoms and a group —C(NH)NR5R6, R1 to R3, R5 andR6 each independently are an organic radical having 1 to 20 C atoms orhydrogen, and the organic radical having 1 to 20 C atoms for R1 to R6 isa saturated or unsaturated acyclic hydrocarbon radical containing noheteroatoms; wherein the mixture β) is present in an amount of 10 to 60mol % less than the amount needed for reaction of the active epoxygroups of the one or more epoxy resins α) and the amine functions of themixture β), and such that the hardener component a) is present in anamount of 0.4 to 0.9 amine equivalent per epoxide equivalent of the oneor more epoxy resins α).
 2. The blend according to claim 1, wherein thehardener component a) consists of said one or more amines having afunctionality≧2.
 3. The blend according to claim 1, wherein the hardenercomponent a) comprises at least two hardener components a1) and a2), thehardener component a1) being at least one polyetheramine having afunctionality≧2 and the hardener component a2) being at least onefurther amine having a functionality≧2.
 4. The blend according to claim3, wherein the hardener component a1) is selected from the groupconsisting of 3,6-dioxa-1,8-octanediamine;4,7,10-trioxa-1,13-tridecanediamine; 4,7-dioxa-1,10-decanediamine;4,9-dioxa-1,12-dodecanediamine; polyetheramine based on triethyleneglycol with an average molar mass of 148; difunctional, primarypolyetheramine prepared by aminating an ethylene glycol grafted withpropylene oxide, with an average molar mass of 176; difunctional,primary polyetheramine based on propylene oxide with an average molarmass of 4000; difunctional, primary polyetheramine prepared by aminatinga polyethylene glycol grafted with propylene oxide, with an averagemolar mass of 2003; aliphatic polyetheramine based on polyethyleneglycol grafted with propylene oxide, with an average molar mass of 900;aliphatic polyetheramine based on polyethylene glycol grafted withpropylene oxide, with an average molar mass of 600; difunctional,primary polyetheramine prepared by aminating a diethylene glycol graftedwith propylene oxide, with an average molar mass of 220; aliphaticpolyetheramine based on a copolymer of poly(tetramethylene ether glycol)and polypropylene glycol with an average molar mass of 1000; aliphaticpolyetheramine based on a copolymer of poly(tetramethylene ether glycol)and polypropylene col with an average molar mass of 1900; aliphaticpolyetheramine based on a copolymer of poly(tetramethylene ether glycol)and polypropylene glycol with an average molar mass of 1400;polyethertriamine based on an at least trihydric alcohol grafted withbutylene oxide, with an average molar mass of 400; aliphaticpolyetheramine prepared by aminating alcohols grafted with butyleneoxide, with an average molar mass of 219; polyetheramine based onpentaerythritol and propylene oxide with an average molar mass of 600;difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 2000; difunctional, primary polyetheraminebased on polypropylene glycol with an average molar mass of 230;difunctional, primary polyetheramine based on polypropylene glycol withan average molar mass of 400; trifunctional, primary polyetheramineprepared by reacting propylene oxide with trimethylolpropane, followedby amination of the terminal OH groups, with an average molar mass of403; trifunctional, primary polyetheramine prepared by reactingpropylene oxide with glycerol, followed by amination of the terminal OHgroups, with an average molar mass of 5000; and a polyetheramine havingan average molar mass of 400, prepared by aminating polyTHF which has anaverage molar mass of 250; and the hardener component a2) is selectedfrom the group consisting of 1,12-diaminododecane; 1,10-diaminodecane;1,2-diaminocyclohexane; 1,2-propanediamine;1,3-bis(aminomethyl)cyclohexane; 1,3-propanediamine;1-methyl-2,4-diaminocyclohexane; 2,2′-oxybis(ethylamine);3,3′-dimethyl-4,4′-diaminodicyclohexylmethane; 4,4′-methylenedianiline;4-ethyl-4-methylamino-1-octylamine; diethylenetriamine; ethylenediamine;hexamethylenediamine; isophoronediamine; menthenediamine;xylylenediamine; N-aminoethylpiperazine; neopentanediamine;norbornanediamine; octamethylenediamine; piperazine;4,8-diaminotricyclo[5.2.1.0]decane; tolylenediamine;triethylenetetramine; and trimethylhexamethylenediamine.
 5. The blendaccording to claim 3, wherein the hardener component a1) is selectedfrom the group consisting of: difunctional, primary polyetheramine basedon polypropylene glycol, with an average molar mass of 230;difunctional, primary polyetheramine based on polypropylene glycol, withan average molar mass of 400; aliphatic difunctional, primarypolyetheramine based on polypropylene glycol, with an average molar massof 2000; difunctional, primary polyetheramine prepared by aminating adiethylene glycol grafted with propylene oxide, with an average molarmass of 220; trifunctional, primary polyetheramine prepared by reactingpropylene oxide with trimethylolpropane, followed by amination of theterminal OH groups, with an average molar mass of 403; aliphaticpolyetheramine based on polyethylene glycol grafted with propyleneoxide, with an average molar mass of 900; aliphatic polyetheramine basedon a copolymer of poly(tetramethylene ether glycol) and polypropyleneglycol, with an average molar mass of 1000; aliphatic polyetheraminebased on a copolymer of poly(tetramethylene ether glycol) andpolypropylene glycol, with an average molar mass of 1900; aliphaticpolyetheramine based on a copolymer of poly(tetramethylene ether glycol)and polypropylene glycol, with an average molar mass of 1400;polyethertriamine based on an at least trihydric alcohol grafted withbutylene oxide, with an average molar mass of 400; aliphaticpolyetheramine prepared by aminating alcohols grafted with butyleneoxide, with an average molar mass of 219; trifunctional, primarypolyetheramine prepared by reacting propylene oxide with glycerol,followed by amination of the terminal OH groups, with an average molarmass of 5000; and the hardener component a2) is selected from the groupconsisting of isophoronediamine; aminoethylpiperazine; 1,3bis(aminoethyl)cyclohexane; and triethylenetetramine; wherein the ratioof a1) to a2) ranges from 0.1 to 10:1.
 6. The blend according to claim3, wherein the hardener component a1) is selected from the groupconsisting of: difunctional, primary polyetheramine based onpolypropylene glycol, with an average molar mass of 230; difunctional,primary polyetheramine based on polypropylene glycol, with an averagemolar mass of 400; trifunctional, primary polyetheramine prepared byreacting propylene oxide with trimethylolpropane, followed by aminationof the terminal OH groups, with an average molar mass of 403;trifunctional, primary polyetheramine prepared by reacting propyleneoxide with glycerol, followed by amination of the terminal OH groups,with an average molar mass of 5000; the hardener component a2) isselected from the group consisting of isophoronediamine;aminoethylpiperazine; 1,3-bis(aminomethyl)cyclohexane; andtriethylenetetraamine; and the hardener component b) istetramethylguanidine; wherein the ratio of a1) to a2) ranges from 1.5 to10:1.
 7. The blend according to claim 1, wherein the radicals R1 to R3,R5, and R6 of the compounds of the formula I are each independentlyselected from the group consisting of hydrogen, methyl, ethyl, n-propyl,isopropyl, n-butyl, and sec-butyl; and R4 is selected from the groupconsisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,and a group —C(NH)NR5R6-.
 8. The blend according to claim 1, wherein theblend further comprises reinforcing-fiber material.
 9. A process forpreparing the blend according to claim 1, which comprises mixing one ormore epoxy resins α) with the mixture β) at temperatures below theinitial curing temperature of the hardener component a).
 10. A curedepoxy resin obtained by a process comprising curing the blend accordingto claim
 1. 11. The cured epoxy resin according to claim 10, wherein thecured epoxy resin is a molding.
 12. A molding according to claim 11,which is fiber-reinforced.
 13. The molding according to claim 12,wherein the molding is a reinforced component for rotor blades of windturbines.
 14. The molding according to claim 12, obtained by a processcomprising lining a mold with a reinforcing-fiber material; introducingthe blend according to claim 1 into the mold with infusion technology;and curing the blend in the mold.